Automatic vehicle-washing systems are well-known, and are in widespread use for washing passenger automobiles, trucks, buses, railroad equipment, and the like. A typical system includes a conveyor for moving the vehicle through the installation, and a series of power-driven brushes which are moved around the vehicle under a drenching spray of water and soap or detergent to remove dirt and grease. The washed vehicle is given a drenching spray of clean rinse water, and is then moved to a drying station, with final drying of windows and bright metal parts usually being completed by hand.
Operating economy and the need for water conservation dictate recovery and reuse of the contaminated water collected in a floor trench beneath the vehicle path. Fresh makeup water must also be introduced to supplement lost water (typically five to ten gallons) carried out of the system by each vehicle. Recovered water is usually quite dirty, and particulates and oily residues must be removed from the contaminated water before recycling through the system.
A typical filter system for vehicle wash water is shown in U.S. Pat. No. 4,104,164, and this system is useful in many such installations. This arrangement, and other commercially available filter systems, are not ideal, however, in that they use filter elements which must be backwashed rather frequently. Backwashing is a technical step requiring a reasonably skilled operator to manipulate valves and other controls to achieve the necessary backflow and routing of contaminate flow to a sewage line. There is need for a simple filter system which can be operated and maintained by unskilled personnel, and it is to this need that our invention is partially directed.
Another problem with known systems is with prevention of bacteria and algae growth in water storage tanks. Absent frequent tank cleaning, and addition of sterilizing chemicals to the tanks, the water soon becomes contaminated and acquires a strong and unpleasant odor. An important feature of our new system is the use of constant recirculation which suppresses growth of bacteria and algae, and accompanying odor.
The new system is ideally suited for recycling of water in vehicle washing installations, but is not limited to this application, and is believed useful in other kinds of installations benefitting from recovery and filtered recycling of contaminated water.